Linux: Add getdents64 system call
Commit Message
No 32-bit system call wrapper is added because the interface
is problematic because it cannot deal with 32-bit inode numbers
and 64-bit directory hashes.
A future commit will deprecate the undocumented getdirentries
and getdirentries64 functions.
2019-05-15 Florian Weimer <fweimer@redhat.com>
Linux: Add getdents64 system call.
* include/dirnent.h (getdents): Add comment and change buffer
argument type to void *.
(getdents64): Likewise. Add hidden prototype.
* sysdeps/unix/sysv/linux/bits/Versions (GLIBC_2.30): Export
getdents64.
* sysdeps/unix/sysv/linux/Makefile [$(subdir) == dirent] (tests):
Add tst-getdents64.
* sysdeps/unix/sysv/linux/bits/unistd_ext.h (getdents64): Declare.
* sysdeps/unix/sysv/linux/getdents.c (__getdents): Change buffer
argument type to void *.
* sysdeps/unix/sysv/linux/getdents64.c (__getdents64): Likewise.
Add hidden definition and getdents64 alias.
* sysdeps/unix/sysv/linux/mips/mips64/getdents64.c (__getdents64):
Likewise.
* sysdeps/unix/sysv/linux/tst-getdents64.c: New file.
* manual/filesys.texi (Accessing Directories): Add Low-level
Directory Access node reference.
(Opening a Directory): Cross-reference it.
(Low-level Directory Access): New node.
* sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.30): Add
getdents64.
* sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/csky/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
(GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.30): Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.30):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.30):
Likewise.
Comments
On 5/15/19 11:10 AM, Florian Weimer wrote:
> No 32-bit system call wrapper is added because the interface
> is problematic because it cannot deal with 32-bit inode numbers
> and 64-bit directory hashes.
Are you saying we do not want to ever add a getdents syscall wrapper
because it would have problems that users couldn't fix, or problems
the user could fix if they were careful?
> A future commit will deprecate the undocumented getdirentries
> and getdirentries64 functions.
Why are getdirentries and getdirentries64 considered deprecated?
Is it because getdents and getdents64 superseded them?
> 2019-05-15 Florian Weimer <fweimer@redhat.com>
>
> Linux: Add getdents64 system call.
> * include/dirnent.h (getdents): Add comment and change buffer
> argument type to void *.
> (getdents64): Likewise. Add hidden prototype.
> * sysdeps/unix/sysv/linux/bits/Versions (GLIBC_2.30): Export
> getdents64.
> * sysdeps/unix/sysv/linux/Makefile [$(subdir) == dirent] (tests):
> Add tst-getdents64.
> * sysdeps/unix/sysv/linux/bits/unistd_ext.h (getdents64): Declare.
> * sysdeps/unix/sysv/linux/getdents.c (__getdents): Change buffer
> argument type to void *.
> * sysdeps/unix/sysv/linux/getdents64.c (__getdents64): Likewise.
> Add hidden definition and getdents64 alias.
> * sysdeps/unix/sysv/linux/mips/mips64/getdents64.c (__getdents64):
> Likewise.
> * sysdeps/unix/sysv/linux/tst-getdents64.c: New file.
> * manual/filesys.texi (Accessing Directories): Add Low-level
> Directory Access node reference.
> (Opening a Directory): Cross-reference it.
> (Low-level Directory Access): New node.
> * sysdeps/unix/sysv/linux/aarch64/libc.abilist (GLIBC_2.30): Add
> getdents64.
> * sysdeps/unix/sysv/linux/alpha/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/arm/libc.abilist (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/csky/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/hppa/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/i386/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/ia64/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/microblaze/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/nios2/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
> (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/sh/libc.abilist (GLIBC_2.30): Likewise.
> * sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/x86_64/64/libc.abilist (GLIBC_2.30):
> Likewise.
> * sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist (GLIBC_2.30):
> Likewise.
>
> diff --git a/NEWS b/NEWS
> index 0e4c57f273..5eb9d05c22 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -20,7 +20,7 @@ Major new features:
> twalk function, but it passes an additional caller-supplied argument
> to the callback function.
>
> -* On Linux, the gettid and tgkill functions have been added.
> +* On Linux, the getdents64, gettid, and tgkill functions have been added.
OK.
>
> * Minguo (Republic of China) calendar support has been added as an
> alternative calendar for the following locales: zh_TW, cmn_TW, hak_TW,
> diff --git a/include/dirent.h b/include/dirent.h
> index 400835eefe..3736803bce 100644
> --- a/include/dirent.h
> +++ b/include/dirent.h
> @@ -35,10 +35,14 @@ extern __ssize_t __getdirentries (int __fd, char *__restrict __buf,
> size_t __nbytes,
> __off_t *__restrict __basep)
> __THROW __nonnull ((2, 4));
> -extern __ssize_t __getdents (int __fd, char *__buf, size_t __nbytes)
> - attribute_hidden;
> -extern __ssize_t __getdents64 (int __fd, char *__buf, size_t __nbytes)
> +
> +/* These functions are only implemented on Linux. The public
> + interface for getdents64 is declared in <unistd.h>. */
> +extern __ssize_t __getdents (int __fd, void *__buf, size_t __nbytes)
> attribute_hidden;
> +extern __ssize_t __getdents64 (int __fd, void *__buf, size_t __nbytes);
> +libc_hidden_proto (__getdents64)
> +
We use void*, but the linux man pages use 'struct linux_dirent64', what should we use?
> extern int __alphasort64 (const struct dirent64 **a, const struct dirent64 **b)
> __attribute_pure__;
> extern int __versionsort64 (const struct dirent64 **a,
> diff --git a/manual/filesys.texi b/manual/filesys.texi
> index 28480e7608..aa4a44dc96 100644
> --- a/manual/filesys.texi
> +++ b/manual/filesys.texi
> @@ -242,6 +242,7 @@ here to the stream facilities for ordinary files, described in
> * Scanning Directory Content:: Get entries for user selected subset of
> contents in given directory.
> * Simple Directory Lister Mark II:: Revised version of the program.
> +* Low-level Directory Access:: Async-signal-functions for directory access.
Please use:
"AS-Safe functions for directory access." ("AS-safe" is defined in the safety notes)
or
"Asynchronous-signal-safe functions for directory access."
> @end menu
>
> @node Directory Entries
> @@ -360,6 +361,10 @@ You shouldn't ever allocate objects of the @code{struct dirent} or
> you. Instead, you refer to these objects using the pointers returned by
> the following functions.
>
> +Directory streams are a high-level interface. On Linux, alternative
> +interfaces for accessing directories using file descriptors are
> +available. @xref{Low-level Directory Access}.
Should this be:
"available in @xref{Low-level Directory Access}."
Rather than having the @xref as a distinct sentence?
> +
> @deftypefun {DIR *} opendir (const char *@var{dirname})
> @standards{POSIX.1, dirent.h}
> @safety{@prelim{}@mtsafe{}@asunsafe{@ascuheap{}}@acunsafe{@acsmem{} @acsfd{}}}
> @@ -826,6 +831,39 @@ After the call the returned entries are available for direct use.
> Note the simple selector function in this example. Since we want to see
> all directory entries we always return @code{1}.
>
> +@node Low-level Directory Access
> +@subsection Low-level Directory Access
> +
> +The stream-based directory functions are not async-signal-safe and
> +cannot be used after @code{vfork}. The functions below provide an
> +alternative that can be used in these contexts.
> +
> +Directory data is obtained from a file descriptor, as created by the
> +@code{open} function, with or without the @code{O_DIRECTORY} flag.
> +@xref{Opening and Closing Files}.
Should this reference be parenthetical?
e.g. ... flag (@xref{Opening and Closing Files}).
> +
> +@deftypefun ssize_t getdents64 (int @var{fd}, void *@var{buffer}, size_t @var{length})
> +@standards{Linux, unistd.h}
> +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
> +The @code{getdents64} function reads at most @var{length} bytes of
> +directory entry data from the file descriptor @var{fd} and stores it
> +into the byte array starting at @var{buffer}.
> +
> +On success, the function returns the number of bytes written to the
> +buffer. This number is zero if @var{fd} is already at the end of the
> +directory stream. On error, the function returns @code{-1} and sets
> +@code{errno} to the appropriate error code.
> +
> +The data is stored as a sequence of @code{struct dirent64} records,
OK. Confirmed layout and checked it against linux man page docs.
> +which can be traversed using the @code{d_reclen} member. The buffer
> +should be large enough to hold the largest possible directory entry.
> +Note that some file systems support file names longer than
> +@code{NAME_MAX} bytes (e.g., because they support up to 255 Unicode
> +characters), so a buffer size of at least 1024 is recommended.
> +
OK.
> +This function is specific to Linux.
OK.
> +@end deftypefun
> +
>
> @node Working with Directory Trees
> @section Working with Directory Trees
> diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> index d2f0b60ea9..afcdc658b5 100644
> --- a/sysdeps/unix/sysv/linux/Makefile
> +++ b/sysdeps/unix/sysv/linux/Makefile
> @@ -188,6 +188,7 @@ inhibit-glue = yes
>
> ifeq ($(subdir),dirent)
> sysdep_routines += getdirentries getdirentries64
> +tests += tst-getdents64
OK.
> tests-internal += tst-readdir64-compat
> endif
>
> diff --git a/sysdeps/unix/sysv/linux/Versions b/sysdeps/unix/sysv/linux/Versions
> index c7137e2c2c..1ca102a9e2 100644
> --- a/sysdeps/unix/sysv/linux/Versions
> +++ b/sysdeps/unix/sysv/linux/Versions
> @@ -175,7 +175,7 @@ libc {
> getcpu;
> }
> GLIBC_2.30 {
> - gettid; tgkill;
> + getdents64; gettid; tgkill;
OK.
> }
> GLIBC_PRIVATE {
> # functions used in other libraries
> diff --git a/sysdeps/unix/sysv/linux/aarch64/libc.abilist b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
> index 324909d553..a4c31932cb 100644
> --- a/sysdeps/unix/sysv/linux/aarch64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/aarch64/libc.abilist
> @@ -2141,6 +2141,7 @@ GLIBC_2.28 thrd_yield F
> GLIBC_2.29 getcpu F
> GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
> GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/alpha/libc.abilist b/sysdeps/unix/sysv/linux/alpha/libc.abilist
> index 084e475569..fe85a35620 100644
> --- a/sysdeps/unix/sysv/linux/alpha/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/alpha/libc.abilist
> @@ -2216,6 +2216,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/arm/libc.abilist b/sysdeps/unix/sysv/linux/arm/libc.abilist
> index f58d16e210..bc3df8dcea 100644
> --- a/sysdeps/unix/sysv/linux/arm/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/arm/libc.abilist
> @@ -126,6 +126,7 @@ GLIBC_2.28 thrd_yield F
> GLIBC_2.29 getcpu F
> GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
> GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/bits/unistd_ext.h b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> index 0061172f23..6e7b2bb83d 100644
> --- a/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> +++ b/sysdeps/unix/sysv/linux/bits/unistd_ext.h
> @@ -22,6 +22,12 @@
>
> #ifdef __USE_GNU
>
> +/* Read from the directory descriptor FD into LENGTH bytes at BUFFER.
> + Return the number of bytes read on success (0 for end of
> + directory), and -1 for failure. */
> +extern ssize_t getdents64 (int __fd, void *__buffer, size_t __length)
> + __THROW __nonnull ((2));
OK.
> +
> /* Return the kernel thread ID (TID) of the current thread. The
> returned value is not subject to caching. Most Linux system calls
> accept a TID in place of a PID. Using the TID to change properties
> diff --git a/sysdeps/unix/sysv/linux/csky/libc.abilist b/sysdeps/unix/sysv/linux/csky/libc.abilist
> index 38f6abaa30..9b3cee65bb 100644
> --- a/sysdeps/unix/sysv/linux/csky/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/csky/libc.abilist
> @@ -2085,6 +2085,7 @@ GLIBC_2.29 xdrstdio_create F
> GLIBC_2.29 xencrypt F
> GLIBC_2.29 xprt_register F
> GLIBC_2.29 xprt_unregister F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/getdents.c b/sysdeps/unix/sysv/linux/getdents.c
> index e796d9354b..3eec4c4221 100644
> --- a/sysdeps/unix/sysv/linux/getdents.c
> +++ b/sysdeps/unix/sysv/linux/getdents.c
> @@ -31,8 +31,10 @@
> /* Pack the dirent64 struct down into 32-bit offset/inode fields, and
> ensure that no overflow occurs. */
> ssize_t
> -__getdents (int fd, char *buf, size_t nbytes)
> +__getdents (int fd, void *buf0, size_t nbytes)
> {
> + char *buf = buf0;
> +
OK. Allowed.
> union
> {
> /* For !_DIRENT_MATCHES_DIRENT64 kernel 'linux_dirent64' has the same
> diff --git a/sysdeps/unix/sysv/linux/getdents64.c b/sysdeps/unix/sysv/linux/getdents64.c
> index 0786a15195..a6dd22106d 100644
> --- a/sysdeps/unix/sysv/linux/getdents64.c
> +++ b/sysdeps/unix/sysv/linux/getdents64.c
> @@ -20,12 +20,14 @@
> #include <dirent.h>
> #include <errno.h>
>
> -/* The kernel struct linux_dirent64 matches the 'struct getdents64' type. */
> +/* The kernel struct linux_dirent64 matches the 'struct dirent64' type. */
OK.
> ssize_t
> -__getdents64 (int fd, char *buf, size_t nbytes)
> +__getdents64 (int fd, void *buf, size_t nbytes)
OK.
> {
> return INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
> }
> +libc_hidden_def (__getdents64)
> +weak_alias (__getdents64, getdents64)
OK.
>
> #if _DIRENT_MATCHES_DIRENT64
> strong_alias (__getdents64, __getdents)
> diff --git a/sysdeps/unix/sysv/linux/hppa/libc.abilist b/sysdeps/unix/sysv/linux/hppa/libc.abilist
> index eb628f907b..75edece94a 100644
> --- a/sysdeps/unix/sysv/linux/hppa/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/hppa/libc.abilist
> @@ -2037,6 +2037,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/i386/libc.abilist b/sysdeps/unix/sysv/linux/i386/libc.abilist
> index 6f240d9a59..edeaf8e722 100644
> --- a/sysdeps/unix/sysv/linux/i386/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/i386/libc.abilist
> @@ -2203,6 +2203,7 @@ GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 vm86 F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/ia64/libc.abilist b/sysdeps/unix/sysv/linux/ia64/libc.abilist
> index e589e3d7e2..b5d460eeb2 100644
> --- a/sysdeps/unix/sysv/linux/ia64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/ia64/libc.abilist
> @@ -2069,6 +2069,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
> index 02c3ceee8d..05633b3cb8 100644
> --- a/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
> @@ -127,6 +127,7 @@ GLIBC_2.28 thrd_yield F
> GLIBC_2.29 getcpu F
> GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
> GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
> index f9a86bd951..47eb7b4608 100644
> --- a/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
> @@ -2146,6 +2146,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/microblaze/libc.abilist b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
> index d153fe0df5..f7ced487f7 100644
> --- a/sysdeps/unix/sysv/linux/microblaze/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/microblaze/libc.abilist
> @@ -2133,6 +2133,7 @@ GLIBC_2.28 thrd_yield F
> GLIBC_2.29 getcpu F
> GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
> GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> index fb3a9b18fc..e49dc4272e 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
> @@ -2120,6 +2120,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> index 22c80418f6..daa3b60c5b 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
> @@ -2118,6 +2118,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/getdents64.c b/sysdeps/unix/sysv/linux/mips/mips64/getdents64.c
> index 8771c3c904..1e22fa4325 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips64/getdents64.c
> +++ b/sysdeps/unix/sysv/linux/mips/mips64/getdents64.c
> @@ -25,8 +25,10 @@
> #include <scratch_buffer.h>
>
> ssize_t
> -__getdents64 (int fd, char *buf, size_t nbytes)
> +__getdents64 (int fd, void *buf0, size_t nbytes)
> {
> + char *buf = buf0;
> +
> #ifdef __NR_getdents64
> ssize_t ret = INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
> if (ret != -1)
> @@ -107,6 +109,9 @@ __getdents64 (int fd, char *buf, size_t nbytes)
> scratch_buffer_free (&tmpbuf);
> return (char *) dp - buf;
> }
> +libc_hidden_def (__getdents64)
> +weak_alias (__getdents64, getdents64)
> +
OK.
> #if _DIRENT_MATCHES_DIRENT64
> strong_alias (__getdents64, __getdents)
> #endif
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> index a32aafb552..457ce0b6f2 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
> @@ -2126,6 +2126,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> index 45342a587e..63d5c03bfb 100644
> --- a/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
> @@ -2120,6 +2120,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/nios2/libc.abilist b/sysdeps/unix/sysv/linux/nios2/libc.abilist
> index fe1e96c170..7fec0c9670 100644
> --- a/sysdeps/unix/sysv/linux/nios2/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/nios2/libc.abilist
> @@ -2174,6 +2174,7 @@ GLIBC_2.28 thrd_yield F
> GLIBC_2.29 getcpu F
> GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
> GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> index cbcad5db98..9200a54309 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
> @@ -2176,6 +2176,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> index 060994eccf..ef7779905f 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
> @@ -2209,6 +2209,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
> index af68ed8d01..2860df8ebc 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/be/libc.abilist
> @@ -2039,6 +2039,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
> index d317dc0586..2229a1dcc0 100644
> --- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/le/libc.abilist
> @@ -2243,6 +2243,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
> index 07d75c0481..31010e6cf7 100644
> --- a/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/riscv/rv64/libc.abilist
> @@ -2103,6 +2103,7 @@ GLIBC_2.28 thrd_yield F
> GLIBC_2.29 getcpu F
> GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
> GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
> index 0fdcd6109c..576295deff 100644
> --- a/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
> @@ -2171,6 +2171,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
> index ca871ad4be..abf0473683 100644
> --- a/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
> @@ -2075,6 +2075,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/sh/libc.abilist b/sysdeps/unix/sysv/linux/sh/libc.abilist
> index b559e5b316..41977f6e9c 100644
> --- a/sysdeps/unix/sysv/linux/sh/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/sh/libc.abilist
> @@ -2041,6 +2041,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
> index 37daaa28e4..3d2f00ca52 100644
> --- a/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
> @@ -2165,6 +2165,7 @@ GLIBC_2.30 __nldbl_vwarn F
> GLIBC_2.30 __nldbl_vwarnx F
> GLIBC_2.30 __nldbl_warn F
> GLIBC_2.30 __nldbl_warnx F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
> index 5f0a3adc3c..2f20643e8e 100644
> --- a/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
> @@ -2092,6 +2092,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/tst-getdents64.c b/sysdeps/unix/sysv/linux/tst-getdents64.c
> new file mode 100644
> index 0000000000..c1f7721221
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/tst-getdents64.c
> @@ -0,0 +1,113 @@
> +/* Test for reading directories with getdents64.
OK.
> + Copyright (C) 2019 Free Software Foundation, Inc.
OK.
> + This file is part of the GNU C Library.
> +
> + The GNU C Library is free software; you can redistribute it and/or
> + modify it under the terms of the GNU Lesser General Public
> + License as published by the Free Software Foundation; either
> + version 2.1 of the License, or (at your option) any later version.
> +
> + The GNU C Library is distributed in the hope that it will be useful,
> + but WITHOUT ANY WARRANTY; without even the implied warranty of
> + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + Lesser General Public License for more details.
> +
> + You should have received a copy of the GNU Lesser General Public
> + License along with the GNU C Library; if not, see
> + <http://www.gnu.org/licenses/>. */
> +
> +#include <dirent.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <stdbool.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <string.h>
> +#include <support/check.h>
> +#include <support/support.h>
> +#include <support/xunistd.h>
> +#include <unistd.h>
OK.
> +
> +static int
> +do_test (void)
> +{
> + /* The test compares the iteration order with readdir64. */
> + DIR *reference = opendir (".");
> + TEST_VERIFY_EXIT (reference != NULL);
> +
> + int fd = xopen (".", O_RDONLY | O_DIRECTORY, 0);
OK.
> + TEST_VERIFY (fd >= 0);
> +
> + /* Perform two passes, with a rewind operating between passes. */
> + for (int pass = 0; pass < 2; ++pass)
> + {
> + /* Check that we need to fill the buffer multiple times. */
> + int read_count = 0;
> +
> + while (true)
> + {
> + /* Simple way to make sure that the memcpy below does not read
> + non-existing data. */
> + struct
> + {
> + char buffer[1024];
> + struct dirent64 pad;
> + } data;
> +
> + ssize_t ret = getdents64 (fd, &data.buffer, sizeof (data.buffer));
> + if (ret < 0)
> + FAIL_EXIT1 ("getdents64: %m");
> + if (ret == 0)
> + break;
> + ++read_count;
> +
> + char *current = data.buffer;
> + char *end = data.buffer + ret;
> + while (current != end)
> + {
> + struct dirent64 entry;
> + memcpy (&entry, current, sizeof (entry));
> + /* Truncate overlong strings. */
> + entry.d_name[sizeof (entry.d_name) - 1] = '\0';
> + TEST_VERIFY (strlen (entry.d_name) < sizeof (entry.d_name) - 1);
> +
> + errno = 0;
> + struct dirent64 *refentry = readdir64 (reference);
> + if (refentry == NULL && errno == 0)
> + FAIL_EXIT1 ("readdir64 failed too early, at: %s",
> + entry.d_name);
> + else if (refentry == NULL)
> + FAIL_EXIT1 ("readdir64: %m");
> +
> + TEST_COMPARE_STRING (entry.d_name, refentry->d_name);
> + TEST_COMPARE (entry.d_ino, refentry->d_ino);
> + TEST_COMPARE (entry.d_off, refentry->d_off);
> + TEST_COMPARE (entry.d_type, refentry->d_type);
OK.
> +
> + /* Offset zero is reserved for the first entry. */
> + TEST_VERIFY (entry.d_off != 0);
> +
> + TEST_VERIFY_EXIT (entry.d_reclen <= end - current);
> + current += entry.d_reclen;
> + }
> + }
> +
> + /* We expect to have reached the end of the stream. */
> + errno = 0;
> + TEST_VERIFY (readdir64 (reference) == NULL);
> + TEST_COMPARE (errno, 0);
> +
> + /* direntries_read has been called more than once. */
> + TEST_VERIFY (read_count > 0);
> +
> + /* Rewind both directory streams. */
> + xlseek (fd, 0, SEEK_SET);
> + rewinddir (reference);
OK.
> + }
> +
> + xclose (fd);
> + closedir (reference);
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
> index c82b3ba7b8..59f85d9373 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
> @@ -2050,6 +2050,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
> GLIBC_2.3.4 setsourcefilter F
> GLIBC_2.3.4 xdr_quad_t F
> GLIBC_2.3.4 xdr_u_quad_t F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
> diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
> index ed89c34c55..67a4e238d6 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
> +++ b/sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist
> @@ -2149,6 +2149,7 @@ GLIBC_2.28 thrd_yield F
> GLIBC_2.29 getcpu F
> GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
> GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
> +GLIBC_2.30 getdents64 F
> GLIBC_2.30 gettid F
> GLIBC_2.30 tgkill F
> GLIBC_2.30 twalk_r F
>
@@ -20,7 +20,7 @@ Major new features:
twalk function, but it passes an additional caller-supplied argument
to the callback function.
-* On Linux, the gettid and tgkill functions have been added.
+* On Linux, the getdents64, gettid, and tgkill functions have been added.
* Minguo (Republic of China) calendar support has been added as an
alternative calendar for the following locales: zh_TW, cmn_TW, hak_TW,
@@ -35,10 +35,14 @@ extern __ssize_t __getdirentries (int __fd, char *__restrict __buf,
size_t __nbytes,
__off_t *__restrict __basep)
__THROW __nonnull ((2, 4));
-extern __ssize_t __getdents (int __fd, char *__buf, size_t __nbytes)
- attribute_hidden;
-extern __ssize_t __getdents64 (int __fd, char *__buf, size_t __nbytes)
+
+/* These functions are only implemented on Linux. The public
+ interface for getdents64 is declared in <unistd.h>. */
+extern __ssize_t __getdents (int __fd, void *__buf, size_t __nbytes)
attribute_hidden;
+extern __ssize_t __getdents64 (int __fd, void *__buf, size_t __nbytes);
+libc_hidden_proto (__getdents64)
+
extern int __alphasort64 (const struct dirent64 **a, const struct dirent64 **b)
__attribute_pure__;
extern int __versionsort64 (const struct dirent64 **a,
@@ -242,6 +242,7 @@ here to the stream facilities for ordinary files, described in
* Scanning Directory Content:: Get entries for user selected subset of
contents in given directory.
* Simple Directory Lister Mark II:: Revised version of the program.
+* Low-level Directory Access:: Async-signal-functions for directory access.
@end menu
@node Directory Entries
@@ -360,6 +361,10 @@ You shouldn't ever allocate objects of the @code{struct dirent} or
you. Instead, you refer to these objects using the pointers returned by
the following functions.
+Directory streams are a high-level interface. On Linux, alternative
+interfaces for accessing directories using file descriptors are
+available. @xref{Low-level Directory Access}.
+
@deftypefun {DIR *} opendir (const char *@var{dirname})
@standards{POSIX.1, dirent.h}
@safety{@prelim{}@mtsafe{}@asunsafe{@ascuheap{}}@acunsafe{@acsmem{} @acsfd{}}}
@@ -826,6 +831,39 @@ After the call the returned entries are available for direct use.
Note the simple selector function in this example. Since we want to see
all directory entries we always return @code{1}.
+@node Low-level Directory Access
+@subsection Low-level Directory Access
+
+The stream-based directory functions are not async-signal-safe and
+cannot be used after @code{vfork}. The functions below provide an
+alternative that can be used in these contexts.
+
+Directory data is obtained from a file descriptor, as created by the
+@code{open} function, with or without the @code{O_DIRECTORY} flag.
+@xref{Opening and Closing Files}.
+
+@deftypefun ssize_t getdents64 (int @var{fd}, void *@var{buffer}, size_t @var{length})
+@standards{Linux, unistd.h}
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+The @code{getdents64} function reads at most @var{length} bytes of
+directory entry data from the file descriptor @var{fd} and stores it
+into the byte array starting at @var{buffer}.
+
+On success, the function returns the number of bytes written to the
+buffer. This number is zero if @var{fd} is already at the end of the
+directory stream. On error, the function returns @code{-1} and sets
+@code{errno} to the appropriate error code.
+
+The data is stored as a sequence of @code{struct dirent64} records,
+which can be traversed using the @code{d_reclen} member. The buffer
+should be large enough to hold the largest possible directory entry.
+Note that some file systems support file names longer than
+@code{NAME_MAX} bytes (e.g., because they support up to 255 Unicode
+characters), so a buffer size of at least 1024 is recommended.
+
+This function is specific to Linux.
+@end deftypefun
+
@node Working with Directory Trees
@section Working with Directory Trees
@@ -188,6 +188,7 @@ inhibit-glue = yes
ifeq ($(subdir),dirent)
sysdep_routines += getdirentries getdirentries64
+tests += tst-getdents64
tests-internal += tst-readdir64-compat
endif
@@ -175,7 +175,7 @@ libc {
getcpu;
}
GLIBC_2.30 {
- gettid; tgkill;
+ getdents64; gettid; tgkill;
}
GLIBC_PRIVATE {
# functions used in other libraries
@@ -2141,6 +2141,7 @@ GLIBC_2.28 thrd_yield F
GLIBC_2.29 getcpu F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2216,6 +2216,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -126,6 +126,7 @@ GLIBC_2.28 thrd_yield F
GLIBC_2.29 getcpu F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -22,6 +22,12 @@
#ifdef __USE_GNU
+/* Read from the directory descriptor FD into LENGTH bytes at BUFFER.
+ Return the number of bytes read on success (0 for end of
+ directory), and -1 for failure. */
+extern ssize_t getdents64 (int __fd, void *__buffer, size_t __length)
+ __THROW __nonnull ((2));
+
/* Return the kernel thread ID (TID) of the current thread. The
returned value is not subject to caching. Most Linux system calls
accept a TID in place of a PID. Using the TID to change properties
@@ -2085,6 +2085,7 @@ GLIBC_2.29 xdrstdio_create F
GLIBC_2.29 xencrypt F
GLIBC_2.29 xprt_register F
GLIBC_2.29 xprt_unregister F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -31,8 +31,10 @@
/* Pack the dirent64 struct down into 32-bit offset/inode fields, and
ensure that no overflow occurs. */
ssize_t
-__getdents (int fd, char *buf, size_t nbytes)
+__getdents (int fd, void *buf0, size_t nbytes)
{
+ char *buf = buf0;
+
union
{
/* For !_DIRENT_MATCHES_DIRENT64 kernel 'linux_dirent64' has the same
@@ -20,12 +20,14 @@
#include <dirent.h>
#include <errno.h>
-/* The kernel struct linux_dirent64 matches the 'struct getdents64' type. */
+/* The kernel struct linux_dirent64 matches the 'struct dirent64' type. */
ssize_t
-__getdents64 (int fd, char *buf, size_t nbytes)
+__getdents64 (int fd, void *buf, size_t nbytes)
{
return INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
}
+libc_hidden_def (__getdents64)
+weak_alias (__getdents64, getdents64)
#if _DIRENT_MATCHES_DIRENT64
strong_alias (__getdents64, __getdents)
@@ -2037,6 +2037,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2203,6 +2203,7 @@ GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 vm86 F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2069,6 +2069,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -127,6 +127,7 @@ GLIBC_2.28 thrd_yield F
GLIBC_2.29 getcpu F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2146,6 +2146,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2133,6 +2133,7 @@ GLIBC_2.28 thrd_yield F
GLIBC_2.29 getcpu F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2120,6 +2120,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2118,6 +2118,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -25,8 +25,10 @@
#include <scratch_buffer.h>
ssize_t
-__getdents64 (int fd, char *buf, size_t nbytes)
+__getdents64 (int fd, void *buf0, size_t nbytes)
{
+ char *buf = buf0;
+
#ifdef __NR_getdents64
ssize_t ret = INLINE_SYSCALL_CALL (getdents64, fd, buf, nbytes);
if (ret != -1)
@@ -107,6 +109,9 @@ __getdents64 (int fd, char *buf, size_t nbytes)
scratch_buffer_free (&tmpbuf);
return (char *) dp - buf;
}
+libc_hidden_def (__getdents64)
+weak_alias (__getdents64, getdents64)
+
#if _DIRENT_MATCHES_DIRENT64
strong_alias (__getdents64, __getdents)
#endif
@@ -2126,6 +2126,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2120,6 +2120,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2174,6 +2174,7 @@ GLIBC_2.28 thrd_yield F
GLIBC_2.29 getcpu F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2176,6 +2176,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2209,6 +2209,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2039,6 +2039,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2243,6 +2243,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2103,6 +2103,7 @@ GLIBC_2.28 thrd_yield F
GLIBC_2.29 getcpu F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2171,6 +2171,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2075,6 +2075,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2041,6 +2041,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2165,6 +2165,7 @@ GLIBC_2.30 __nldbl_vwarn F
GLIBC_2.30 __nldbl_vwarnx F
GLIBC_2.30 __nldbl_warn F
GLIBC_2.30 __nldbl_warnx F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2092,6 +2092,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
new file mode 100644
@@ -0,0 +1,113 @@
+/* Test for reading directories with getdents64.
+ Copyright (C) 2019 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <support/check.h>
+#include <support/support.h>
+#include <support/xunistd.h>
+#include <unistd.h>
+
+static int
+do_test (void)
+{
+ /* The test compares the iteration order with readdir64. */
+ DIR *reference = opendir (".");
+ TEST_VERIFY_EXIT (reference != NULL);
+
+ int fd = xopen (".", O_RDONLY | O_DIRECTORY, 0);
+ TEST_VERIFY (fd >= 0);
+
+ /* Perform two passes, with a rewind operating between passes. */
+ for (int pass = 0; pass < 2; ++pass)
+ {
+ /* Check that we need to fill the buffer multiple times. */
+ int read_count = 0;
+
+ while (true)
+ {
+ /* Simple way to make sure that the memcpy below does not read
+ non-existing data. */
+ struct
+ {
+ char buffer[1024];
+ struct dirent64 pad;
+ } data;
+
+ ssize_t ret = getdents64 (fd, &data.buffer, sizeof (data.buffer));
+ if (ret < 0)
+ FAIL_EXIT1 ("getdents64: %m");
+ if (ret == 0)
+ break;
+ ++read_count;
+
+ char *current = data.buffer;
+ char *end = data.buffer + ret;
+ while (current != end)
+ {
+ struct dirent64 entry;
+ memcpy (&entry, current, sizeof (entry));
+ /* Truncate overlong strings. */
+ entry.d_name[sizeof (entry.d_name) - 1] = '\0';
+ TEST_VERIFY (strlen (entry.d_name) < sizeof (entry.d_name) - 1);
+
+ errno = 0;
+ struct dirent64 *refentry = readdir64 (reference);
+ if (refentry == NULL && errno == 0)
+ FAIL_EXIT1 ("readdir64 failed too early, at: %s",
+ entry.d_name);
+ else if (refentry == NULL)
+ FAIL_EXIT1 ("readdir64: %m");
+
+ TEST_COMPARE_STRING (entry.d_name, refentry->d_name);
+ TEST_COMPARE (entry.d_ino, refentry->d_ino);
+ TEST_COMPARE (entry.d_off, refentry->d_off);
+ TEST_COMPARE (entry.d_type, refentry->d_type);
+
+ /* Offset zero is reserved for the first entry. */
+ TEST_VERIFY (entry.d_off != 0);
+
+ TEST_VERIFY_EXIT (entry.d_reclen <= end - current);
+ current += entry.d_reclen;
+ }
+ }
+
+ /* We expect to have reached the end of the stream. */
+ errno = 0;
+ TEST_VERIFY (readdir64 (reference) == NULL);
+ TEST_COMPARE (errno, 0);
+
+ /* direntries_read has been called more than once. */
+ TEST_VERIFY (read_count > 0);
+
+ /* Rewind both directory streams. */
+ xlseek (fd, 0, SEEK_SET);
+ rewinddir (reference);
+ }
+
+ xclose (fd);
+ closedir (reference);
+ return 0;
+}
+
+#include <support/test-driver.c>
@@ -2050,6 +2050,7 @@ GLIBC_2.3.4 setipv4sourcefilter F
GLIBC_2.3.4 setsourcefilter F
GLIBC_2.3.4 xdr_quad_t F
GLIBC_2.3.4 xdr_u_quad_t F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F
@@ -2149,6 +2149,7 @@ GLIBC_2.28 thrd_yield F
GLIBC_2.29 getcpu F
GLIBC_2.29 posix_spawn_file_actions_addchdir_np F
GLIBC_2.29 posix_spawn_file_actions_addfchdir_np F
+GLIBC_2.30 getdents64 F
GLIBC_2.30 gettid F
GLIBC_2.30 tgkill F
GLIBC_2.30 twalk_r F